A vehicle suspension mechanism adapted to control roll steer is disclosed in, for example, Japanese Provisional Patent Publication No. 47-24015. The suspension mechanism herein disclosed comprises a suspension arm pivotally connected to the vehicle body by means of two eccentric bolts. The suspension arm is thus rockable with respect to the vehicle body about an axis which is adjustable by turning one or both of the eccentric bolts. The toe and camber angles of the road wheel can be adjusted by varying the angular position of the suspension arm about the axis of rocking motion thereof. A drawback is encountered in a prior-art suspension mechanism of this nature in that, when the axis of rocking motion of the suspension arm is adjusted as above noted, the suspension arm is caused to tilt laterally of the vehicle body and as a consequence the toe angle of the road wheel fails to become zero degrees when the angle of roll of the vehicle body is at zero degrees and vice versa. (This is graphically indicated by curve a in FIG. 5 of the drawings.) It is for this reason impossible to have the roll steer characteristics of the vehicle body varied depending upon the performance of the tires and other parameters affecting the performance characteristics of the suspension system with one of the toe angle and the angle of body roll maintained at zero degrees when the other thereof becomes zero degrees.
It is, accordingly, an important object of the present invention to provide an improved vehicle suspension mechanism capable of varying the roll steer characteristics of the vehicle body depending upon the performance of the tires and other parameters affecting the performance characteristics of the suspension system with one of the toe angle and the angle of body roll maintained at zero degrees when the other thereof becomes zero degrees.
It is another important object of the present invention to provide an improved vehicle suspension mechanism featuring, particularly, a suspension arm which is arranged in such a manner as to be rockable about an axis fixed with respect to the vehicle body and which nevertheless permits adjustment of the axis of rotation of a road wheel with respect of the axis of rocking motion of the suspension arm.